- Product Overview
- 3-Zone Hot Air Vial Depyrogenation Tunnel
- Batch / Cabinet Type Depyrogenation Oven
- Tunnel vs Batch Oven: Which One Do You Need?
- Inside a 3-Zone Tunnel: Heating, Sterilizing, Cooling
- Technical Specifications
- Tunnel Validation: A 5-Step How-To
- USP, EP, and Annex 1 Compliance
- Inline Integration with Washer and Filling
- Frequently Asked Questions
- Installation, Validation, and Support
- Request a Quote
Product Overview
A vial depyrogenation tunnel is the critical thermal-processing step between the vial washer and the aseptic filling machine on any sterile injectable line. It uses sustained dry heat (300–340 °C in the sterilizing zone) to destroy bacterial endotoxin (LPS) on the inner surface of washed glass vials, delivering an Fh ≥ 1000 and ≥ 3-log endotoxin reduction so the vial can enter the Grade A aseptic filling zone pre-sterilized and pyrogen-free. Two configurations dominate pharmaceutical production:
- 3-Zone Hot Air Sterilizing Tunnel — continuous in-line conveyor system with heating, sterilizing, and cooling zones under HEPA-filtered ISO 5 / Grade A laminar airflow. Throughput 100–400 vials/min. Used in commercial parenteral and vaccine manufacturing.
- Batch / Cabinet Type Depyrogenation Oven — static hot-air chamber for small batches, clinical supplies, and stability samples. 60–120 minute cycles, programmable recipes, FDA 21 CFR Part 11-ready controller.
Both machines are fabricated from SS 316L stainless steel with Ra ≤ 0.4 µm contact surfaces, HEPA-filtered air handling, and full IQ/OQ documentation for WHO-GMP, EU GMP Annex 1, and USFDA injectable facilities.
340 °C
Sterilizing-zone temperature
Fh ≥ 1000
Dry-heat lethality
≥ 3 log
Endotoxin reduction
ISO 5
Grade A laminar airflow
3-Zone Hot Air Vial Depyrogenation Tunnel
What it is and when to use it
The 3-Zone Hot Air Vial Depyrogenation Tunnel is a continuous in-line conveyor sterilizer. Washed, WFI-rinsed vials enter Zone 1 (pre-heat) and are progressively brought up to the sterilizing temperature. In Zone 2, the vials are held at 300–340 °C on a stainless steel mesh belt for the residence time needed to hit Fh ≥ 1000. In Zone 3, the vials are cooled back to ≤ 30 °C under HEPA-filtered ISO 5 / Grade A laminar airflow before they exit directly into the aseptic filling machine. Output: up to 400 vials/min of sterile, pyrogen-free, cool-to-touch vials.
Use this machine when: you run a commercial parenteral or vaccine line with bulk unsterilized vials, need continuous in-line processing, and have to meet USP <85>, USP <788>, EU GMP Annex 1, and USFDA 21 CFR 211.94 requirements.
Key Engineering Features
- 3-zone temperature control: independent PID loops for pre-heat, sterilizing, and cooling zones with redundant thermocouples and a 21 CFR Part 11 audit trail.
- HEPA-filtered laminar flow: H13 / H14 HEPA filters on the cooling zone deliver ISO 5 / Grade A unidirectional airflow; in-line DOP / PAO integrity test port.
- SS 316L contact parts: belt, guides, and ducting in AISI 316L with Ra ≤ 0.4 µm electropolished finish, fully drainable, no dead legs.
- Steam or electric / gas heat: choose from steam-coil heat exchangers (clean steam preferred), electric resistance heaters, or LPG / natural gas fired burners with a heat-recovery loop.
- Variable-speed belt drive: VFD-controlled mesh belt with electronic tensioning; speed 50–600 mm/s matched to the upstream washer and downstream filler.
- Insulated housing: double-wall SS 304 skin with 50 mm ceramic-fiber insulation; skin temperature ≤ 45 °C at full load, safe to touch.
- PLC + HMI control: Siemens / Allen-Bradley PLC, 10″ color touchscreen, recipe storage for vial formats, real-time Fh calculation, alarm history, and full audit trail.
- Safety and access: CE marked per EN 60204-1, full guarding, interlocked access doors, emergency stops, overtemperature protection, and a one-touch cool-down sequence.
Specifications — 3-Zone Hot Air Tunnel
| Parameter | Specification |
|---|---|
| Throughput | 100–400 vials/minute, depending on vial format |
| Vial Size Range | 2 ml–100 ml tubular glass vials conforming to ISO 8362-1 |
| Vial Diameter | 14 mm–52 mm |
| Vial Height | 30 mm–115 mm |
| Zone 1 Temperature (Pre-Heat) | Ambient temperature to 200°C |
| Zone 2 Temperature (Sterilizing) | 300°C–340°C at the validated set point |
| Zone 3 Temperature (Cooling) | ≤ 30°C at the tunnel exit |
| Fh Value Delivered | ≥ 1000, typically 1200–1500 with a safety margin |
| Endotoxin Reduction | ≥ 3-log reduction, validated according to USP <85> |
| Total Dwell Time | 7–15 minutes, depending on vial format and operating speed |
| Belt Width | 600 mm / 900 mm / 1,200 mm |
| Belt Material | SS316L balanced-weave mesh belt |
| Belt Drive | VFD-controlled drive with electronic belt tensioning |
| Heating Source | Steam at 3–5 bar / electric heating / LPG or natural gas |
| Contact Parts | SS316L stainless steel, electropolished to Ra ≤ 0.4 µm |
| Non-Contact Skin | SS304 stainless steel with 50 mm ceramic-fibre insulation and surface temperature ≤ 45°C |
| Laminar Airflow | ISO 5 / Grade A airflow with H13 / H14 HEPA filtration, rated at 99.99% efficiency at 0.3 µm MPPS |
| Power Supply | 415 V AC, 3-phase, 50–60 Hz |
| Connected Load | 35–60 kW, depending on the model |
| Steam Consumption | 80–180 kg/hour for steam-heated models |
| Cooling Water | 2–3 bar, 1,200–2,500 litres/hour |
| Compressed Air | 6–8 bar oil-free compressed air, 200–400 litres/minute |
| Exhaust | Ducted exhaust to atmosphere with backflow prevention |
| Noise Level | ≤ 78 dB(A) |
| Tunnel Footprint | 3,500–6,500 mm L × 1,200–1,500 mm W × 1,900 mm H |
| Machine Weight | 2,500–5,500 kg |
| Warranty | 12 months comprehensive warranty with lifetime technical support |
Batch / Cabinet Type Vial Depyrogenation Oven
What it is and when to use it
The Batch / Cabinet Type Vial Depyrogenation Oven is a static hot-air chamber used for small batches, clinical supplies, stability samples, and laboratory-grade depyrogenation. Vials are loaded on stainless steel trays, the chamber is sealed, the air is heated by electric or steam coils with HEPA-filtered recirculation, and the cycle runs for 60–120 minutes at 250–300 °C. A programmable controller delivers a validated Fh ≥ 1000 cycle with full 21 CFR Part 11 audit trail.
Use this machine when: you run clinical / Phase-I / Phase-II batches, need stability and sterility-test sample preparation, run small-volume niche injectables, or need a backup depyrogenation method for tunnel downtimes.
Key Engineering Features
- Programmable recipes: stored cycles for 250 °C / 30 min, 300 °C / 60 min, and 300 °C / 120 min, with end-of-cycle cooling to ≤ 40 °C.
- HEPA-filtered recirculation: H13 HEPA on the recirculation loop keeps the chamber air clean and the vial exteriors particle-free.
- SS 316L interior: all chamber walls, shelves, and trays in AISI 316L with Ra ≤ 0.4 µm; SS 304 outer skin with 75 mm mineral-wool insulation.
- Validation port: 4–8 thermal validation ports on the side wall for IQ/OQ thermocouple mapping studies.
- 21 CFR Part 11 controller: recipe access by user ID, electronic signatures, full audit trail, and Ethernet / USB data export.
- Multiple safety layers: overtemperature cutout, door interlock, overpressure relief, and a manual release latch in case of power loss.
- Castor / leveling feet: lockable heavy-duty castors on smaller units, anti-vibration leveling feet on larger chambers.
Specifications — Batch / Cabinet Oven
| Parameter | Specification |
|---|---|
| Chamber Volume | 200 L / 400 L / 800 L / 1,200 L |
| Operating Temperature | Ambient temperature + 10°C up to 300°C |
| Temperature Uniformity | ±2°C at 250°C after stabilization |
| Cycle Time | 60–120 minutes, depending on the selected recipe |
| Fh Value Delivered | ≥ 1000 with a validated operating recipe |
| Heating Source | Electric stainless-steel finned heaters or steam coil |
| Heating Power | 6–18 kW, depending on the model |
| Chamber Construction | Fully welded SS316L stainless steel, finished to Ra ≤ 0.4 µm |
| Outer Skin | SS304 stainless steel with 75 mm mineral-wool insulation |
| Air Recirculation | H13 HEPA-filtered air circulation at 800–2,000 m³/hour |
| Trays Included | 2–6 SS316L perforated trays, each measuring 600 × 400 mm |
| Validation Ports | 4–8 DN 25 silicone-pad validation ports |
| Controller | PLC with 7-inch colour HMI, 21 CFR Part 11-ready |
| Power Supply | 415 V AC, 3-phase, 50–60 Hz |
| Compressed Air | 4–6 bar oil-free compressed air, 30–50 litres/minute |
| Exhaust | DN 80 ducted exhaust to atmosphere with backflow prevention |
| Chamber Footprint | 900–1,800 mm W × 800–1,500 mm D × 1,200–1,800 mm H |
| Chamber Weight | 350–1,200 kg |
| Warranty | 12 months comprehensive warranty with lifetime technical support |
Tunnel vs Batch Oven: Which Depyrogenator Do You Need?
The choice between a continuous 3-zone tunnel and a batch or cabinet oven depends on throughput, batch size and production-line integration. The right configuration should match your product mix, facility layout and validation requirements.
| Parameter | 3-Zone Tunnel | Batch / Cabinet Oven |
|---|---|---|
| Mode | Continuous in-line conveyor operation | Static batch or cabinet operation |
| Throughput | 100–400 vials per minute; up to 600 VPM with a dual-belt configuration | 1–8 batches per day |
| Cycle Time | 7–15 minutes residence time per vial | 60–120 minutes per batch |
| Loading | Direct in-line feeding from the vial washing machine | Manual loading of vials or components on trays |
| Final Rinse | Not required because the vial washer is installed upstream | Not applicable |
| Capital Cost (USD) | $75K–$200K | $20K–$80K |
| Best For | Commercial parenteral, vaccine and lyophilized injectable production lines | Clinical batches, stability samples, niche injectables and backup depyrogenation |
| Footprint | Approximately 3.5–6.5 metres of production-line length | Approximately 0.9–1.8 metres of cabinet footprint |
| Validation Burden | High: heat-distribution studies, endotoxin challenge and Fh mapping across all three zones | Moderate: heat-distribution validation for each chamber loading pattern |
| Operator Skill | Low, with recipe-driven PLC and HMI operation | Moderate, due to manual tray loading and batch handling |
| Common Downstream | Cooling zone followed by aseptic filling using rotary piston, peristaltic or time-pressure systems | Manual transfer to a Grade A aseptic zone or restricted access barrier system |
| Particle Performance | Suitable for meeting USP <788> requirements for parenteral products | Suitable for meeting USP <788> when HEPA air recirculation is validated |
Rule of Thumb:
For continuous production involving more than one batch per shift, a 3-zone depyrogenation tunnel is generally required. For small clinical, stability or development batches, a batch oven is usually sufficient and more economical. Many commercial parenteral facilities install both: a tunnel for routine production and a smaller oven for stability samples, retained samples and method-validation work.
For continuous production involving more than one batch per shift, a 3-zone depyrogenation tunnel is generally required. For small clinical, stability or development batches, a batch oven is usually sufficient and more economical. Many commercial parenteral facilities install both: a tunnel for routine production and a smaller oven for stability samples, retained samples and method-validation work.
Inside a 3-Zone Tunnel: Pre-Heat, Sterilize, Cool
Each vial spends 7–15 minutes inside the 3-zone tunnel, depending on format, belt speed, and zone setpoints. The temperature profile is the heart of the depyrogenation performance.
- Zone 1 — Pre-heat (Ambient → 200 °C): Vials enter at room temperature on a moving mesh belt. Recirculated hot air from the sterilizing zone is partially bypassed into the pre-heat zone, gradually raising the vial surface and interior toward the sterilizing temperature. The pre-heat zone typically has 2–3 temperature probes and a proportional damper to control heat transfer without thermal shock.
- Zone 2 — Sterilizing (300–340 °C): The critical zone. Vials are held at the validated sterilizing setpoint for the residence time required to deliver Fh ≥ 1000 across the entire load. Multiple thermocouples (typically 8–12) monitor the actual vial surface temperature in real time; the controller logs the temperature profile and calculates the achieved Fh for every run. A drop in Fh below the validated limit triggers an alarm and a reject signal at the tunnel exit.
- Zone 3 — Cooling (≤ 30 °C at exit): Vials are cooled by HEPA-filtered ISO 5 / Grade A laminar airflow before they reach the aseptic filling infeed. Cooling is critical: a vial that exits the tunnel too hot will create a thermal updraft in the Grade A zone, disrupting unidirectional flow and increasing particle counts. Cooling-zone HEPA integrity is tested in place (DOP / PAO) annually.
Throughout the cycle, the controller logs zone temperatures, belt speed, HEPA pressure drop, and Fh calculation to a 21 CFR Part 11 audit trail. The data is exported via Ethernet for batch records.
Tunnel Validation: A 5-Step How-To
Validation is non-negotiable for any aseptic injectable line. The following sequence is a practical, audit-tested approach used by our customers’ QA teams. It aligns with WHO TRS 986 Annex 2, EU GMP Annex 1 (2022), 21 CFR 211.94, and the relevant USP chapters.
Step 1 — Define user requirements and worst-case load.
Document the smallest and largest vial formats, the highest-tolerated endotoxin load on incoming vials, the target Fh value (≥ 1000), the air-flow class (ISO 5 / Grade A), and the line speed. Lock these in a User Requirements Specification (URS) before ordering.
Step 2 — Perform IQ and OQ on the installed tunnel.
Run the IQ checklist (utilities, instrumentation, materials of construction, HEPA integrity, calibration) followed by OQ tests (no-vial empty cycle, alarm verification, sensor calibration, interlock function) over 3 consecutive successful runs. Document deviations and resolutions.
Step 3 — Perform heat distribution and heat penetration studies.
Load the tunnel with the worst-case vial pattern and place calibrated thermocouples in at least 10 positions including the slowest-heating corners. Run 3 consecutive cycles and verify Fh ≥ 1000 in the slowest vial with a safety margin of at least 20%.
Step 4 — Conduct endotoxin challenge studies.
Spike vials with USP Reference Standard Endotoxin (typically 10⁴ – 10⁶ EU per vial). Run the tunnel under the validated recipe. Test the vials post-tunnel by LAL per USP <85> and confirm ≥ 3-log endotoxin reduction. Repeat for 3 runs in the slowest-heating position.
Step 5 — Compile the validation report and ongoing monitoring plan.
Issue the final validation report signed by QA, engineering, and production. Define ongoing monitoring: continuous temperature and pressure logging, HEPA integrity test annually, endotoxin re-challenge annually or after any major change, and a revalidation trigger schedule.
Estimated timeline: 4–6 weeks from IQ start to final report, depending on lab turnaround. Estimated cost: $10,000 – $18,000 in QA and lab fees for a single vial format.
USP, EP, and Annex 1 Compliance
Every machine is engineered and documented against the following standards:
- USP <85> — Bacterial Endotoxin Test (LAL)
- USP <788> — Particulate Matter in Injections
- USP <789> — Particulate Matter in Ophthalmic Solutions
- USP <1207> — Container Integrity (for sealed-container validation)
- EP 2.6.14 — Bacterial Endotoxins
- EP 2.9.19 — Particulate Contamination: Sub-visible Particles
- EU GMP Annex 1 (2022) — Manufacture of Sterile Medicinal Products
- 21 CFR 211.94 — Drug Product Containers and Closures
- 21 CFR Part 11 — Electronic Records and Signatures
- WHO TRS 986 Annex 2 — WHO GMP for Pharmaceutical Products
- ISO 9001:2015 — Quality Management
- CE Machinery Directive 2006/42/EC
- ISPE Baseline® Guide — Sterile Product Manufacturing Facilities
Inline Integration with Washer and Filling
A vial depyrogenation tunnel is the middle of a tightly synchronized line:
- Upstream: Vial unscrambler (for bulk vials) or nest/tub de-bagger (for RTU vials)
- Washer: Rotary gripper (or external) — washed and WFI-rinsed vials feed the tunnel
- Depyrogenation Tunnel: 3-zone hot-air tunnel at 300–340 °C, Fh ≥ 1000, endotoxin reduction ≥ 3 log
- Cooling Zone: vial cooling to ≤ 30 °C under ISO 5 / Grade A laminar airflow
- Aseptic Filling: rotary piston or peristaltic filling under Grade A unidirectional airflow
- Stoppering: rubber stopper placement and pre-pressing
- Capping: aluminium cap sealing (if not done in the stopper star-wheel)
- Inspection: automated visual inspection for particles, cracks, fill volume, stopper presence
Our tunnels are designed for direct feed from our rotary gripper washers, with matched conveyor speed, pitch, and entry/exit height. The tunnel exit is fitted with an integrated cooling conveyor that connects directly to the filling machine’s infeed star-wheel.
Frequently Asked Questions
A vial depyrogenation tunnel is a continuous in-line hot-air sterilizer that destroys bacterial endotoxin on the interior of washed glass vials before aseptic filling. It reaches 300–340 °C and delivers Fh ≥ 1000, allowing the vial to enter the Grade A filling zone pre-sterilized and pyrogen-free.
A 3-zone tunnel has a pre-heat zone, a sterilizing zone at 300–340 °C, and a cooling zone with HEPA-filtered laminar airflow. Vials travel on a stainless mesh belt, with matched entry and exit speeds so no operator handling is needed between wash and aseptic filling.
Fh is the equivalent dry-heat sterilization time at 170 °C, calculated from the actual time-temperature profile. Fh ≥ 1000 delivers ≥ 3-log endotoxin reduction — the threshold recognized by USP <85>, EP 2.6.14, FDA 21 CFR 211.94, and WHO TRS 986.
Sterilization destroys viable microbes. Depyrogenation specifically targets bacterial endotoxin, which is far more heat-resistant. LPS survives standard autoclaving at 121 °C, so depyrogenation needs sustained dry heat at ≥ 250 °C — hence a dedicated depyrogenation tunnel, not an autoclave.
Validation follows a 3-stage approach: heat distribution / heat penetration mapping, endotoxin challenge with USP Reference Standard Endotoxin, and ongoing monitoring with calibrated probes and 21 CFR Part 11 audit trail. Annual revalidation is required.
415V AC 3-phase power, 35–60 kW connected load; 6–8 bar oil-free compressed air; steam (3–5 bar) for steam-heated models or LPG / NG for gas-fired; cooling water at 2–3 bar; HEPA filters (H13 / H14) for laminar flow; and an exhaust vent with backflow prevention.
Standard 3-zone tunnels handle 2 ml – 100 ml tubular glass vials (ISO 8362-1), 14–52 mm diameter, 30–115 mm height. Custom tunnels are available for moulded glass, syringes, cartridges, and infusion bottles up to 1 litre.
Standard 3-zone tunnels process 100–400 vials per minute for 2–50 ml formats. High-capacity dual-belt tunnels reach 600 vials per minute. Total tunnel residence time is 7–15 minutes including pre-heat, sterilize, and cool.
Yes. The tunnel is designed for inline integration with an upstream rotary gripper or external vial washer and a downstream aseptic filling machine. Belt speed, pitch, and entry / exit height are matched to eliminate operator handling.
A tunnel is a continuous in-line conveyor system for high-volume production (100–600 vials/min). An oven is a static chamber for small batches, clinical supplies, and stability samples (60–120 min cycles). Tunnels serve commercial lines; ovens serve clinical and small-batch settings.
Customer Outcomes
“Our previous dry-heat oven was a bottleneck for clinical supply. The 3-zone tunnel lets us run 240 vials/min continuous for our Phase-III vaccine, and we passed the FDA pre-approval inspection without a single observation on the depyrogenation step.”
— Plant Director, Vaccine Manufacturer, Pune (reference available on request)
“Endotoxin post-tunnel dropped below the LAL detection limit (0.001 EU/ml) on every run. The validated Fh of 1,350 gives us a comfortable safety margin and our QA team stopped flagging the depyrogenation step in batch records.”
— Head of QA, Generics Injectables Manufacturer, Ahmedabad (reference available under NDA)
“The 3-zone tunnel integrated with our rotary gripper washer and time-pressure filler in 11 days from delivery to first good batch. The HMI recipes for 2 ml, 10 ml, and 50 ml formats were a one-touch changeover.”
— Project Engineer, CDMO, Boston, USA (reference available on request)
Installation, Validation, and Support
Every machine is delivered as a turnkey project with the following scope:
- Pre-shipment Factory Acceptance Test (FAT) at our facility, with empty-cycle temperature mapping and Fh data
- On-site installation, commissioning, and Site Acceptance Test (SAT)
- IQ and OQ execution support, including protocol walkthrough with your QA team
- Operator and maintenance training (typically 4 days)
- 1-year comprehensive warranty covering parts and labor
- Lifetime remote support via video call, TeamViewer, and WhatsApp business
- Annual Maintenance Contract (AMC) options including preventive maintenance, HEPA integrity testing, and recalibration
- Spare parts kits shipped within 24–48 hours globally from regional warehouses
Typical delivery times: Standard 3-zone tunnels ship in 10–14 weeks; batch ovens in 6–8 weeks. Installation and validation typically add 2–4 weeks on site.
Industries We Serve
- Pharmaceutical and biopharmaceutical manufacturing
- Vaccine and biological manufacturing
- Lyophilized (freeze-dried) injectables
- Sterile ophthalmic and nasal sprays
- Veterinary injectables
- Contract development and manufacturing organizations (CDMOs)
Certifications and Compliance
- ISO 9001:2015 Certified Manufacturing
- CE Marking (Machinery Directive 2006/42/EC)
- cGMP-Compliant Design
- WHO-GMP Compatible
- USFDA-Ready Configurations
- EU GMP Annex 1 (2022) Compatible
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